Simulation of radar reflectivities using a mesoscale weather forecast model

A three-dimensional radar simulation model (RSM) using predicted fields of a nonhydrostatic mesoscale weather forecast model, the Lokal-Modell (LM) with 2.8 km resolution, has been developed. The LM output data include the fields of the simulated hydrometeor types to study realistic cloud and precipitation fields, covering all stages of precipitation development. The RSM is able to simulate radar reflectivity measurements of any kind of radar situated within the model domain and hence allows a quick quality control of the predicted hydrometeor components. We show comparisons of simulated measurements with real measurements of a C-band radar and an X-band radar of a squall line at midlatitudes. Another application of the RSM is analytical studies using realistic physical structures of the atmosphere as given by the LM, e.g., the relation between three-dimensional reflectivity fields and the surface rain rate. The RSM is a useful,tool for (1) the validation, and hence improvement, of mesoscale models and (2) the estimation of some of the errors related to the determination of the surface rain rate.